Rectangular filtered arc plasma source

Abstract

An apparatus is disclosed for generating oppositely directed streams of plasma for the purpose of depositing a coating or performing ion processing. The plasma comprises ionized vapor of a cathode material, generated by vacuum arc evaporation from a linear magnetron cathode. The plasma is diverted by a deflection electrode to a substrate region, while the macroscopic droplets of cathode material also generated by the arc are intercepted and prevented from reaching the substrate. Magnetic means are disclosed for controlling the arc motion on the cathode surface while simultaneously deflecting and guiding the plasma. The source may be extended indefinitely in length, permitting coating or ion processing of large substrates.

What I claim is: 
     
       1. An apparatus for generating oppositely directed plasma streams comprising ionized vapor of a cathode material, said apparatus comprising cathode means, filter means, magnetic means, arc power supply means, and anode means; said apparatus having oppositely facing output apertures from which said plasma streams are emitted; said cathode means being connected to the negative output of said arc power supply means and functioning to emit material comprising plasma and macroparticles of said cathode material; said cathode means having an evaporable surface from which said emission occurs; said cathode having substantially the shape of a rectangular bar having four long sides and two ends; said evaporable surface consisting of two opposite long sides and both ends of said bar;   said filter means comprising deflector means and cathode side shield means; said filter means functioning to transmit at least part of said plasma to said substrate region while preventing or reducing transmission of said macroparticles;   said deflector means comprising at least two deflector surfaces; each of said deflector surfaces mounted parallel to and facing one of said long sides of said evaporable surface; said deflector means functioning to deflect said plasma emitted by said cathode into two directions parallel to said deflector surfaces;   said side shield means comprising at least two surfaces mounted on opposite sides of said evaporable surface and projecting outward from said evaporable surface by a selected distance; said side shield means functioning to prevent at least a portion of said macroparticles emitted from said evaporable surface from reaching said output apertures;   said magnetic means comprising at least one permanent magnet or electromagnet and functioning to generate a magnetic field in the region between said cathode means and deflector means, said magnetic field having flux lines substantially parallel to said evaporable surface and said deflector surfaces;   said anode means comprising at least one surface in electrical contact with said plasma, said anode means being connected to the positive output of said arc power supply means.   
     
     
       2. The apparatus as in claim 1 in which said magnetic means comprises at least 2 magnet assemblies, each assembly comprising at least 2 permanent magnets separated by at least one magnetically permeable pole piece; said magnet assemblies being disposed parallel to each other and to said deflector means; and in which said cathode means and deflector means are disposed between said magnet assemblies. 
     
     
       3. The apparatus as in claim 1 or 2 further comprising a deflector bias power supply having its positive output connected to said deflector surfaces and its negative output connected to said anode means.